2023 Practice Questions Block 6 (Physics 0625) These are some sample questions for the newly added Space Physics block to help prepare for the upcoming exams for physics 0620! This study pack includes the following: 1. 20 Questions of various sizes and various points of focus. 2. IGCSE-like marking schemes for the questions. 3. Model answers to each question to use as reference. Note… Please know that these questions are mainly ones that I came up with myself and answered, some of these questions are also picked out from the Feb/March 2023 exams or ma be rephrased. The answers were all checked using the book and some AI. MST_Creator Website Instagram, Twitter, DeviantArt, NG & Tumblr Questions Question 1: The asteroid belt is what splits the gas giants from the rocky planets; write down the planet which comes after and before the asteroid belt. [2 marks] Question 2: The solar system is made up of 8 planets: Planet Density (gm/cm3) Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune 5.4 5.2 5.5 3.9 1.3 0.7 1.3 1.6 Explain why the first four planets are denser than the last four planets [4 marks] Question 3: The distance between galaxies is measured using a unit called “light year”. State what is meant by the term light year. [1 mark] Question 4: All the planets in the solar system orbit around the sun. State which stage of a star’s lifestyle our sun is at. [1 mark] Notes By MST_CREATOR Page 1 Instagram, Twitter, DeviantArt, NG & Tumblr Question 5: A star was found recently by scientists, they found out that it is a black dwarf. List the stages this star went through. • • • • • • [3 marks] Question 6: Express the size of one lightyear in meters. [1 mark] Question 7: Show that the size of one light year is 9.5 × 1012 km [3 marks] Question 8: State the difference between redshift and blueshift. [2 marks] Question 9: Name the galaxy the Solar System is located in. [1 mark] Notes By MST_CREATOR Page 2 Instagram, Twitter, DeviantArt, NG & Tumblr Question 10: Our sun is a main sequence star. Suggest its later stages in its life cycle. [3 marks] Question 11: Betelgeuse is a red supergiant located in the Orion constellation. Suggest what will happen to the supergiant in the later stages of its life cycle. [2 marks] Question 12: Show that the universe is 14 billion years old using Hubble’s constant. [4 marks] Question 13: Explain what is meant by CMBR. [3 marks] Question 14: Jupiter has an average orbital distance of 778 million kilometres and takes around 11.86 Earth years to complete a revolution around the sun. Note that one Earth day is 24 hours. Calculate the orbital speed of Jupiter in ms-1. [3 marks] Question 15: State the quantity that the redshift of a galaxy is used to calculate. [1 mark] Notes By MST_CREATOR Page 3 Instagram, Twitter, DeviantArt, NG & Tumblr Question 16: Explain the formation of the sun and the planets using the accretion model. You explanation must also include the formation of the inner and outer planets. [6 marks] Question 17: One of the types of radiation emitted by the sun is Ultra Violet radiation. List 2 other types of radiation emitted by the sun. [2 marks] Question 18: Name the 4 inner planets in the solar system. [1 mark] Question 19: The gravitational field strength on Mercury is 4 N/kg and the gravitational field strength on Earth is 9 N/kg. Explain why this is the case despite Mercury being closer to the sun than Earth. [3 marks] Question 20: Explain what redshift is and how it provides evidence for the expansion of the universe. [5 marks] Notes By MST_CREATOR Page 4 Instagram, Twitter, DeviantArt, NG & Tumblr Mark Scheme Question 1 Answer Before: Mars Mark 2 After: Jupiter 2 Award one mark for each mentioned point (max 4): • 4 First four planets are made up of dense elements closer to the sun • Last four planets are made up of lighter elements farther from the sun • Size of the planets is influenced by their distance from the sun and force of gravity (1 mark) • Inner planets are smaller due to the increased force they experienced from the sun (1 mark) • Outer planets are larger due to experiencing less force of gravity (1 mark) 3 The distance travelled in (the vacuum of) space by light in one year 1 4 Main sequence star 1 5 Award one mark per two correct points: 3 • Gas and dust • Protostar • Main sequence • Red giant • White Dwarf • Black Dwarf 6 9.5 × 1015 1 7 Avoid one mark per point: 3 • Must show the use of D = ST • Must show clear and logical working to reach the answer. • Must use speed of light as 3×108 Notes By MST_CREATOR Page 5 Instagram, Twitter, DeviantArt, NG & Tumblr Question Answer Mark 8 Award one mark for correct definition of either redshift or blueshift. 2 Award one mark for explanation suggesting that blueshift is caused by the moving towards of spatial entities from the observer or redshift is caused by the moving away of spatial entities from the observer. 9 10 Milky way 1 Award one mark per point: 3 • Correctly identifying the next stage after the main sequence phase (red giant). • Mentioning the subsequent stage after the red giant (white dwarf). • Identifying the final stage of a star's life cycle, after the white dwarf phase (black dwarf). 11 12 Award one mark per idea: • Betelgeuse will become unstable and result in a supernova • Either it becomes a black hole or a neutron star. Award one mark for the use of the formula: 2 4 1 π΄ππ = ′ π»π’ππππ π πΆπππ π‘πππ‘ Award one mark for proper conversions. Award up to two marks for proper calculations and logic behind the answer. 13 Award one mark for each idea (3 max): • 3 Microwave radiation is observed at all points in space around the Earth. • Radiation was produced when the Universe was formed • This radiation has expanded into the microwave region of the electromagnetic spectrum • This is evidence that the Universe expanded Notes By MST_CREATOR Page 6 Instagram, Twitter, DeviantArt, NG & Tumblr Question 14 Answer Award one mark per point: Mark 3 • 13,070 ms-1 • Uses the formal π ππππ = • Correct conversions and logical method 2ππ π‘ in any form 15 Change of wavelength (which occurs when galaxy is moving quickly) 16 • One mark for correct general explanation of the formation of the 1 6 sun and planets. • Two marks for correct explanation of the formation of inner planets. • Two marks for correct explanation of the formation of outer planets. • 17 One mark for clear, concise, well-structured, and logical answer. Award one mark for each: • Visible light • Infrared Radiation 18 Mercury, Venus, Earth, and Mars 19 • Explanation that the gravitational field strength is dependent on 2 1 3 mass and distance from the sun. • Correctly identifying that Earth is heavier than Mercury. • Explanation that the greater mass of Earth compensates for its greater distance from the sun, leading to a higher gravitational field strength than Mercury. 20 • Redshift is when the observed wavelength is greater than the 5 actual wavelength o …due to the motion of objects. • Explaining the Doppler Effect. • Explaining how Doppler Effect causes redshift in the light from galaxies. • Redshift provides an estimate of the rate of expansion o …how this is done using the amount of redshift in the light from galaxies Notes By MST_CREATOR Page 7 Instagram, Twitter, DeviantArt, NG & Tumblr My Answers (Model Answers) Question 1: The asteroid belt is what splits the gas giants from the rocky planets; write down the planet which comes after and before the asteroid belt. Before: Mars After: Jupiter [2 marks] Question 2: The solar system is made up of 8 planets: Planet Density (gm/cm3) Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune 5.4 5.2 5.5 3.9 1.3 0.7 1.3 1.6 Explain why the first four planets are denser than the last four planets When the solar system was still in its early stages and the planets were not made yet, the elements close to the sun were mainly dense elements, this is because the lighter ones existed as liquids or gases. This meant that the first four planets would be made up of the dense and heavy elements, they were also smaller due to the increased force they experienced due to their less distance from the sun. The last four planets however, were made up of lighter elements, this is because the far region did not have high temperatures meaning the lighter elements could exist as solids, this meant that the outer planets would be made up of these light elements. They are also far larger in size when compared to the inner planets because they experienced less force of gravity due to their increased distance from the sun. [4 marks] Notes By MST_CREATOR Page 8 Instagram, Twitter, DeviantArt, NG & Tumblr Question 3: The distance between galaxies is measured using a unit called “light year”. State what is meant by the term light year. A light year refers to the distance travelled by light in the span of one year. [1 mark] Question 4: All the planets in the solar system orbit around the sun. State which stage of a star’s lifestyle our sun is at. It is a main sequence star. [1 mark] Question 5: A star was found recently by scientists, they found out that it is a black dwarf. List the stages this star went through. • Gas and dust • Protostar • Main sequence star • Red giant • White dwarf • Black dwarf [3 marks] Question 6: Express the size of one lightyear in meters. 9.5 × 1015 meters [1 mark] Notes By MST_CREATOR Page 9 Instagram, Twitter, DeviantArt, NG & Tumblr Question 7: Show that the size of one light year is 9.5 × 1012 km Duration of 1 year = 365 days 365 days in seconds = 365 × 24 × 60 × 60 Speed of light = 3 × 108 ms-1 Distance (m) = Speed (ms-1) × Time (s) Distance (m) = 3 × 108 × 365 × 24 × 60 × 60 Distance (m) = 9.5 × 1015 meters Distance (km) = 9.5 × 1015 ÷ 1000 Distance (km) = 9.5 × 1012 km [3 marks] Question 8: State the difference between redshift and blueshift. Redshift is when the observed wavelength is more than the real wavelength as a result of the moving away of galaxies and spatial entities from the observer, this is because the spectrum shifts to the red side of the spectrum. Blue shift is when the observed wavelength is less than the real wavelength as a result of the galaxies and objects moving towards the observer, it is when the spectrum shifts towards the purple side of the spectrum. [2 marks] Question 9: Name the galaxy the Solar System is located in. It is located in the Milky Way. [1 mark] Notes By MST_CREATOR Page 10 Instagram, Twitter, DeviantArt, NG & Tumblr Question 10: Our sun is a main sequence star. Suggest its later stages in its life cycle. As of now, our sun is a main sequence star; this stage will come to an end once it has run out of its hydrogen fuel. This will result in it becoming a red giant. This red giant eventually becomes unstable and releases its outer layers and eventually becomes a white dwarf. His white dwarf will eventually run out of energy and then become a black dwarf. [3 marks] Question 11: Betelgeuse is a red supergiant located in the Orion constellation. Suggest what will happen to the supergiant in the later stages of its life cycle. Betelgeuse is a red supergiant, this means that it will become unstable and result in a supernova. The end of the star is dependent on the size, if it is massive, then it would end up collapsing in on itself and become a black hole. If this is not the case, then it would become a neutron star. [2 marks] Question 12: Show that the universe is 14 billion years old using Hubble’s constant. Hubble’s constant = 2.2 × 10-18 1.27 × 1014 Age = 1 1.44×1010 π»π’ππππ ′ π πΆπππ π‘πππ‘ 1,000,000 Age = 1 2.2 × 10−18 4.55 ×1017 60×60 = 4.55 × 1017s = 1.27 × 1014 βππ’ππ 24×365 14413.54 1000 = 1.44 × 1010 π¦ππππ = 14413.54 πππππππ π¦ππππ = 14.41 πππππππ π¦ππππ 14.41 = 14 πππππππ π¦ππππ (2 π . π) [4 marks] Notes By MST_CREATOR Page 11 Instagram, Twitter, DeviantArt, NG & Tumblr Question 13: Explain what is meant by CMBR. CMBR or Cosmic Microwave Background Radiation is radiation which was released during the big bang; this radiation is still present and is experienced throughout the universe and is of one specific frequency. It is radiation which has expanded into the microwave region of the electromagnetic spectrum. [3 marks] Question 14: Jupiter has an average orbital distance of 778 million kilometres and takes around 11.86 Earth years to complete a revolution around the sun. Note that one Earth day is 24 hours. Calculate the orbital speed of Jupiter in ms-1. πππππ‘ππ πππππ = 2ππ π‘ ππππ (π ) = 11.86 × 365 × 24 × 60 × 60 2π(778×109 ) πππππ‘ππ π·ππ π‘ππππ = 778 × 106 ππ πππππ‘ππ πππππ = 11.86×365×24×60×60 πππππ‘ππ π·ππ π‘ππππ (π) = 778 × 109 πππππ‘ππ πππππ = 13,069.77675 ππ −1 ππππ = 11.86 × 365 πππ¦π πππππ‘ππ πππππ = 13,070 ππ −1 [3 marks] Question 15: State the quantity that the redshift of a galaxy is used to calculate. It is used to calculate the change in wavelength. [1 marks] Notes By MST_CREATOR Page 12 Instagram, Twitter, DeviantArt, NG & Tumblr Question 16: Explain the formation of the sun and the planets using the accretion model. Your explanation must also include the formation of the inner and outer planets. The sun formed as a result of the contraction of a solar nebula, this contraction cause gases and other molecules to form the sun. The planets were formed be the remaining matter. The inner planets were located near the sun, this meant that the area had high temperatures. This caused the lighter elements to become liquids or gases unlike the heavier elements which stayed solid due to their high melting and boiling points. This meant that the inner planets would be made up of dense elements with high melting points. The outer planets are lighter and are made up of the light elements which could exist as solids due to the low temperatures, this lead to them being less dense. They are also large in size, this is because the outer region did not experience lots of gravitational force from the sun. [6 marks] Question 17: One of the types of radiation emitted by the sun is Ultra Violet radiation. List 2 other types of radiation emitted by the sun. • Visible light • Infrared Radiation [2 marks] Question 18: Name the 4 inner planets in the solar system. Mercury, Venus, Earth, and Mars. [1 mark] Notes By MST_CREATOR Page 13 Instagram, Twitter, DeviantArt, NG & Tumblr Question 19: The gravitational field strength on Mercury is 4 N/kg and the gravitational field strength on Earth is 9 N/kg. Explain why this is the case despite Mercury being closer to the sun than Earth. The reason why Earth has a greater gravitational field strength than Mercury is due to the Earth being heavier than Mercury. While it is true that the gravitational field strength decreases as the distance between the object and the sun increases. However, it is also dependent on the mass of the planet, this means that heavier planets have more gravitational field strength as well. When compared, Mercury’s less distance from the sun is not enough to make it have a higher gravitational field strength which is why Earth has more gravitational field strength. [3 marks] Question 20: Explain what redshift is and how it provides evidence for the expansion of the universe. Redshift is when the observed wavelength is more the actual wavelength, this phenomenon is due to the Doppler Effect where the motion of an object causes wavelength of light to expand as it moves away from the observer. In the case of galaxies, it tells us the rate at which the universe is expanding. This is done by calculating the amount that the light from the galaxies have redshifted, this provides us with an estimate of the rate at which the universe is expanding. [5 marks] Notes By MST_CREATOR Page 14 2023 Instagram, Twitter, DeviantArt, NG & Tumblr Practice Questions Block 6 (Physics 0625) These are some sample questions for the newly added Space Physics block to help prepare for the upcoming exams for physics 0620! Final Words I hope this resource was useful for you! This resource is just one of the many resources I have made till now. You can find all the other resources at my website. This includes resources such as revision notes, topical past papers, and other helpful resources. I also work on other projects such as game or software to help with math prep! Notes By MST_CREATOR Page 15
